1. Field of the Invention
The present invention relates to a paper cutting apparatus for a folder, in which in the folder for a web rotary press, when a paper jam occurs on a downstream side of a folding cylinder group, a paper is cut on an upstream side of the folding cylinder group.
2. Description of the Related Art
A folder for a web rotary press includes a former for folding double a continuous paper having passed through a printing section in a widthwise direction, a pair of forming rollers arranged on a downstream side of the former, at least a pair of nipping rollers arranged on a downstream side of the paired forming rollers, and a folding cylinder group arranged on a downstream side of the paired nipping rollers. Also, in order to decrease a contact friction between a former surface and a continuous paper, the folder is constructed so as to have an air blowout port for blowing out air from the former surface.
On the other hand, the folder is provided with a paper jam detector for detecting an occurrence of paper jam on a downstream side of the folding cylinder group. A paper cutting apparatus is provided to cut the paper at a position between the former and the folding cylinder group in the event of the occurrence of paper jam. The technologies for this paper cutting apparatus have been disclosed in Japanese Utility Model Publication No. 55-32744 and Japanese Patent Laid-Open No. 2000-118862.
The technology disclosed in Japanese Utility Model Publication No. 55-32744 will be as described below. The paper cutting apparatus is provided to cut the paper in a paper passage between the paired forming rollers provided under the former of the folder and the paired nipping rollers provided just on the downstream side of the forming rollers. By a paper jam signal sent from the paper jam detector for detecting the occurrence of paper jam in a fan or a conveyor under the folding cylinder group, the paper cutting apparatus cuts the paper and blocks the paper passage to stop the advance of the succeeding paper. The succeeding paper does not enter the machine on the downstream side of the paired forming rollers, but is discharged from the former portion to the outside of the machine.
The technology disclosed in Japanese Patent Laid-Open No. 2000-118862 will be as described below. The paper cutting apparatus is provided to cut the paper in a paper passage between the folding cylinder group of the folder and the paired nipping rollers just on the upstream side of the folding cylinder group. By a paper jam signal sent from the paper jam detector for detecting the occurrence of paper jam in the folding cylinder group, the paper cutting apparatus cuts the paper and blocks the paper passage to stop the advance of the succeeding paper. The succeeding paper does not enter the folding cylinder group, but is discharged to a region deviating from there.
The above-described paper cutting apparatuses of the prior art have the problems as described below.
In the paper cutting apparatus disclosed in Japanese Utility Model Publication No. 55-32744, the preceding paper of the paper having been cut by the paper cutting apparatus, that is, the preceding paper at a distance between the paper cutting apparatus provided on the downstream side near the former and the folding cylinder group enters a portion where the paper jam has occurred before the machine is stopped. Therefore, the paper jam expands accordingly, which may cause a trouble such as damage to the machine.
In the paper cutting apparatus disclosed in Japanese Patent Laid-Open No. 2000-118862, the succeeding paper of the paper having been cut by the paper cutting apparatus provided on the upstream side near the folding cylinder group is discharged to a region at the side of the folding cylinder group.
However, the paired nipping rollers and the folding cylinder group provided on the downstream side of the paired forming rollers are generally surrounded by a cover to ensure safety and insulate sounds. Therefore, the inside of the cover of machine becomes full with a large amount of succeeding paper during the time from the operation of machine at a high speed to the emergency stop in response to the detection of the occurrence of paper jam by the paper jam detector, which may cause a trouble such as damage to the machine due to the stay of paper.
Also, the restoring work against paper jam in the paper jam portion for restarting the machine and the removing work for removing the paper filling within the cover require much time and labor, so that these kinds of work impose a burden on the worker.
An object of the present invention is to provide a paper cutting apparatus for a folder, in which when a paper jam occurs in a folding cylinder group and/or a portion on the downstream side of the folding cylinder group, a paper is cut compulsorily on the upstream side of the folding cylinder group, and the expansion of paper jam caused by the succeeding paper is restrained.
Another object of the present invention is to provide a paper cutting apparatus for a folder, which can easily discharge a cut paper to the outside of the machine.
Still another object of the present invention is to provide cutting means of a mechanism for compulsorily cutting a paper to restrain the expansion of paper jam caused by the succeeding paper when a paper jam occurs in a folding cylinder group and/or a portion on the downstream side of the folding cylinder group.
Still another object of the present invention is to provide a mechanism for easily restraining a flapping behavior of a running paper.
According to the disclosed embodiment, in a folder for a web rotary press which is provided with a forming roller pair and at least one nipping roller pair on the downstream side of the forming roller pair in a paper passage between a former and a folding cylinder group and provided with a paper jam detector for detecting the occurrence of a paper jam at least in the folding cylinder group, a paper cutting apparatus includes first cutting means provided so as to be capable of cutting a paper running between the forming roller pair under the former and the nipping roller pair just on the downstream side of the forming roller pair; second cutting means provided so as to be capable of cutting the paper running between the folding cylinder group and the nipping roller pair just on the upstream side of the folding cylinder group; and control means which receives a paper jam signal generated from the paper jam detector and sends a cutting signal to the first cutting means and the second cutting means.